The eruption of Mount St Helens

Discover how a mountain lost its top in America’s most economically destructive volcanic eruption

Mount St Helens blew off its summit in May 1980 with the energy of 20,000 Hiroshima-size atomic bombs. The resulting rock blast and mudslides killed 57 people and around 7,000 large animals, engulfed 200 houses, choked rivers, buried highways and flattened trees like matchsticks. Ash closed nearby airports for up to two weeks, grounding thousands of flights. The damage cost $1.1 billion to repair. The volcano remains active to this day and it’s America’s second-most dangerous volcano. It sits on the Ring of Fire – a 40,000-kilometre (25,000-mile) horseshoe of volcanoes circling the Pacific Ocean. Beneath Mount St Helens, two of the massive rock plates that form the Earth’s crust are colliding; the oceanic Juan de Fuca Plate is sliding beneath the continental North American Plate. As the ocean plate grinds…

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How It Works Book of Incredible Earth (Digital) - 1 Issue, How It Works Book Of Incredible Earth 6th Edition

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